This park was established to protect a strip of primary and secondary forest at 700 to 2267m. It holds a great diversity of animal and plant species, and guarantees a constant and clean flow for countless water sources for such important rivers as the Toro, Agua Zarcas, Guayabo and Platanar.

As it is located in the Central Volcanic Cordillera, the area's geomorphology is volcanic. Among the main representatitves is the still active Platanar Volcano at 2183 m the inactive Cerro Viejo at 2122m and the erosion caldera of Río Segundo.

This protected area, which is in the process of being acquired by the State, has three life zones: premontane rain-forest, premontane wet forest and lower montane rain forest. Among the forest species are the enormous oaks (Quercus spp.), magnolia (Magnolia poasana), a species typical of the high mountains, quizarras (Ocotea spp and Nectandra spp), the yos (Sapium rigidifolium), the small cedar (Brunellia costaricensis) and the white cypress (Podocarpus macrostachyus).

The fauna is represented by 44 species of amphibians, 32 reptiles, 107 birds and 30 mammals. Among the amphibians and reptiles are the glass frog (Centrolenella euknemos), basilisk (Basiliscus plumifrons), boa (boa constrictor) and fer-de-lance (Bothrops asper). Among the birds, the quetzal (Pharomachrous mocinno), which feeds mainly on small wild avocados, the bat falcon (Falco rufigularis) and the white hawk (Leucopternis albicollis), stand out.

The mammals include Baird's tapir (Tapirus bairdii), which is the biggest land mammal in the country, tayra (Eira Barbara), northen tamandua (Tamandua mexicana), red brocket deer (Manzana Americana) and coyote (Canis latrans), besides 5 of the 6 cat species in Costa Rica.

Archeological finds indicate that the region was a meeting point of cultures from both north and south of the continent. One of the most important chiefdoms in the area before the arrival of the Spanish, was that of the Botos Indians. It extended as far as the Central Valley across the territories of the current Juan Castro Blanco and Póas Volcano National Parks.

Juan Castro Blanco is situated on the Chocosuela mountain chain at the western end of the Central Volcanic Cordillera. The Naranjo-Quesada City and Quesada City-Venecia highways skirt the park to the west and north. One can see the forest that is typical of the region from the grit road to the Toro II hydroelectric project. There is a bus service between San José and Quesada. In Quesada, taxis can be hired.